 four-prong tub, do I need to go to the four-prong outlet instead of having a three-prong? Would that be maybe one of the things? You can't. You legally aren't supposed to do that because if you have a three-prong, that means you have two hots and a ground, and that's the way that wire was set up. So a four-prong is going to have a two-prong and a ground outlet,